【Creative Cultivation Program】T-shirts become cotton clothes? Why did autumn suddenly come in one day?

Have you worn long johns today? A few days ago, were you still wearing T-shirts and shorts, dreaming of going out for fun during the national holidays, but unexpectedly it rained for days and the temperature plummeted, so you could only put on cotton clothes and long johns and stay at home without going out. This summer is so hot that the highest temperature in many places has exceeded 40℃. In early October, some parts of Anhui, Jiangxi and Hubei still had high temperatures of 40℃, but unexpectedly a strong cold air caused autumn to come in one day. What is the reason for this?

Why did the temperature drop suddenly and drastically in the context of global warming?

Global warming is a topic that we are all familiar with and very concerned about. Logically, we should feel that it is getting hotter and hotter. This summer, we did feel the rolling heat wave. The highest temperatures in many provinces and regions such as Shandong reached 37 to 39 degrees Celsius. However, in early October, the temperature suddenly plummeted. The temperature in most parts of central and eastern China dropped by 8 to 12 degrees Celsius. Before we could experience the cool and refreshing autumn weather, we had strong winds and the temperature dropped directly, as if we had fallen into a cold winter.

However, global warming and local temperature changes cannot be generalized. Global warming refers to the trend of rising global average temperature over a long period of time. The heat distribution of the earth itself is uneven, and even the temperature in different regions at the same latitude can vary greatly. This involves the influence of multiple factors such as topography, land and sea, ocean currents, and climate. The combined effect produces differences in climate in different regions. The main factor causing drastic temperature changes in a certain area over a period of time is the adjustment of the weather system; in addition, against the background of global warming, the frequent occurrence of extreme weather and climate events has contributed to the fluctuations in temperature.

For example, the precipitous drop in temperature in most parts of the country in early October was caused by the adjustment of the weather system, which led to the strong cold air moving southward to affect most parts of my country. In some areas, the evenly matched confrontation between cold and warm air caused continuous rainfall. As the saying goes, "an autumn rain brings a chill", which means that every southward movement of cold air causes the temperature to drop to a lower level. So when the autumn rain lasts for a long time, it means that the cold air is strong and persistent, so the temperature this autumn will naturally drop rapidly. Take Shandong as an example. During the National Day holiday, most areas of Shandong received more than 100 mm of precipitation, and some areas received more than 200 mm. This intensity of precipitation rarely occurs in autumn. So why is there so much rain in Shandong this autumn?

Subtropical high pressure and cold air collide to bring heavy rainfall

Many people often hear the meteorological term "subtropical high pressure", but they don't know what it is. Its formation is mainly due to the dual effects of solar radiation and the Coriolis force. The solar radiation in the equatorial region is strong, the air is heated and the temperature rises, the air density decreases, and it will climb to high altitudes and flow toward the poles. Due to the effect of the Coriolis force, the direction of the air flow continues to shift. With the increase of latitude, the Coriolis force gradually increases, and finally in the subtropical region (around 30 degrees), the air flow changes to move from west to east, and hinders the subsequent air from continuing to flow, forcing it to sink and accumulate, forming subtropical high pressure.

The subtropical high pressure is the culprit for the hot weather in summer. Hot air from the equatorial region continues to gather. In the areas controlled by the subtropical high pressure, the sinking of air currents has brought about a significant increase in temperature, making the weather clear and dry, with high temperature and little rain. This is also an important reason why many places in the south suffered from high temperature, little rain and drought this summer.

Where did the heavy rainfall in Shandong come from this autumn? Typhoons Rose and Locke, the 17th and 18th typhoons, brought a lot of moisture to the Pacific Ocean, providing sufficient water vapor for rainfall. Then a strong cold air from the north collided violently with the subtropical high pressure belt. The warm and humid air in the subtropical high pressure belt encountered the cold air and climbed up, cooled and condensed, forming this heavy rainfall.

Because the base temperature was relatively high in the early stage, coupled with strong cold air and heavy precipitation, the local temperature dropped drastically, resulting in the phenomenon of "autumn in one day".

What should we do in the face of a changing climate?

When the climate is abnormal and the weather is changeable, it will bring a certain degree of harm to agriculture, animal husbandry, and our bodies. In the face of abnormal climate, we must enhance our ability to resist disaster risks. In agricultural production, we must develop drought-resistant and cold-resistant crops, shorten the cultivation time, adopt artificial intervention and other methods to cope with extreme climates; at the same time, we must also strengthen exercise, pay attention to work and rest and diet, and enhance our own resistance, so that when the temperature changes drastically, we can avoid the trouble of diseases such as fever and colds.

Humans not only passively adapt to climate change, but also have a huge impact on the climate through their macro-activities. Global warming is the best example. Although our individual power is minimal, when we all pay attention to low-carbon environmental protection and care for the environment, the climate will naturally treat us gently and give us a more livable living environment. Therefore, in our daily lives, we can also do our part to save energy and reduce emissions in response to climate change and fight global warming in our own way, such as taking public transportation and using environmentally friendly materials.